The present invention relates to a method for supporting the middle section of a glass panel to be bent in a mould, in which method the middle section of a glass panel placed on a mould is supported during loading and a preheating process and the support is released at the start of a bending process for allowing the glass panel to deflect so as to be supported by the mould over its middle section as well.
The invention relates also to an apparatus for supporting the middle section of a glass panel to be bent in a mould, said apparatus comprising support elements for the middle section of a glass panel, which are secured to a mould or a mould carriage, as well as elements for releasing the middle support at the start of a bending process.
A problem encountered in the process of bending large glasses, such as windshields for buses or trucks, is that the unsupported span or bearing distance for the middle section of a glass placed on a mould becomes excessively long, whereby the glass may break up upon bending under its own weight during a loading process in a cold condition or in a preheating process prior to reaching a bending temperature. It is prior known to provide a mould with various middle support systems for avoiding the break-up of a glass. However, the prior known middle support systems are such that the implementation thereof is impossible in an automated serial furnace.
It is an object of the invention to provide a method and apparatus for supporting the middle section of a glass panel to be bent in a mould in such a way that the middle support can be implemented also in an automated serial furnace.
A second object of the invention is to provide a method and apparatus, whereby the middle support can be controllably lowered during a bending process.
A third object of the invention is to provide a method and apparatus, whereby the two foregoing objects can be accomplished without having to construct the carriages and moulds with complicated actuators, which are replaced with an actuator common to all moulds and set up in a bending station.
These objects are achieved by means of a method of the invention.
These objects are also achieved by means of an apparatus of the invention.